1. Field of the Invention
The present invention relates to a method for the production of a piston for an internal combustion engine, having a circumferential cooling channel, whereby a blank of a lower piston part is forged, and a blank of an upper piston part is produced, the blanks are pre-machined and joined together to form a piston blank, which is finished to produce a piston. The present invention furthermore relates to a method for the production of a piston for an internal combustion engine, whereby a blank of a lower piston part is forged, and a blank of an upper piston part is produced, the blanks are pre-machined and joined together to form a piston blank, which is finished to produce a piston. Finally, the present invention relates to such pistons for an internal combustion engine.
2. The Prior Art
In forged piston parts, openings such as those for the coolant inflow and the coolant outflow in a cooling channel, for example, have been produced by means of drilling. In this connection, sharp cutting edges occur, at which great stresses can lead to cracks. For this reason, the cutting edges must be rounded off manually or by machine, and this involves much effort. Furthermore, openings that deviate from the circular shape must be milled, with great effort. The excavated grooves for the pin securing rings on the pin bores must also be milled or cast, with great effort.